The invention relates generally to vehicle suspensions, and more particularly to an onboard system for monitoring the performance of a vehicle suspension.
A precision-tuned suspension can be the difference between winning and losing for a competitive motocross rider. Modern suspensions for motocross bikes employ both compression and rebound circuits allowing 12 to a 14 inches of travel to allow riders to perform substantial jumps and to traverse rough terrain. In addition, these suspensions are adjustable to allow optimization based on the weight of the rider, the layout of the racetrack, and the speed with which the rider negotiates the track. However, the importance of high-performance suspension is not limited to motocross racing. Top competitors in such sports as mountain biking, snowmobile racing, and off-road truck racing are fine-tuning their own suspensions to give them an advantage over their rivals. In addition, even non-competitive riders can improve their performance by customizing the suspension of their vehicle.
Unfortunately, it is not enough simply to purchase a vehicle with an adjustable, high-performance suspension. An improperly adjusted suspension can be a disadvantage rather than an advantage if the system fails to compress under impact, compresses too much, or rebounds too quickly. Therefore, a rider can distinguish himself or herself from competitors by understanding how the suspension is responding when the vehicle moves over a particular terrain, and how to make intelligent adjustments to the system to optimize its performance.
Typically, the compression circuit of a suspension should be adjusted to maximize use of the full range of travel without repeatedly undergoing full compression or xe2x80x9cbottoming out.xe2x80x9d This will ensure that the greatest amount of force is absorbed by the suspension rather than the rider. The proper compression adjustment for a rider of a given weight will depend on the character of the terrain since a surface with many small bumps will require lower compression resistance than a surface with several large vertical jumps.
The rebound circuit controls the speed with which the suspension returns to an equilibrium condition after undergoing compression. Typically, the rebound circuit should be adjusted to ensure the system returns to equilibrium before the vehicle encounters the next irregularity in the terrain. However, if the system returns too quickly, it can cause the vehicle to bounce, much like a pogo stick.
While many riders understand the basic functioning of their vehicle suspensions, even the most experienced riders cannot determine necessary adjustments based solely on how the suspension xe2x80x98feelsxe2x80x99 during operation. Because modern suspensions employ a variety of interacting components to insulate the rider from the forces sustained by the vehicle, it is often difficult to determine which component(s) is in need of adjustment. For example, a rider who feels the suspension repeatedly bottoming out, has no way of knowing if the problem is due to insufficient compression resistance or to slow rebound. Moreover, a suspected problem with the suspension at one wheel may actually be caused by an improperly adjusted suspension at another wheel.
The difficulty in determining what adjustments are needed cause many riders to avoid making any adjustments at all, fearing that they will only make matters worse. Other riders attempt to adjust their suspensions by trial and error. However, given the many possible adjustments which can be made, this can be an impractical approach, especially for professional riders who are continually faced with new racetracks. Another approach involves having a person act as a xe2x80x9cspotterxe2x80x9d to watch the vehicle as the rider traverses a track. The spotter attempts to detect whether the suspension is effectively using its full range of travel and whether it is rebounding to its equilibrium position between compressions. However, this method is difficult for even a highly trained technician.
Therefore, it would be desirable to have a system that mounts on a vehicle and provides the rider with information effective to analyze the performance of the vehicle suspension. Preferably, the rider could activate the system and make a test run by operating the vehicle over a selected course. The rider would then be able to adjust their suspension based on the characteristics of the selected course.
The invention provides a vehicle-mountable, suspension monitoring system for producing suspension-analysis information which can be used to determine adjustments to a vehicle suspension that includes a rebound circuit and a compression circuit. The suspension monitoring system includes sensor structure located adjacent a desired section of the vehicle suspension, and a control/processing/display (CPD) unit located adjacent the vehicle operator and connected to communicate with the sensor structure. The CPD unit includes a power source and is manually operable by a vehicle operator. The sensor structure is configured to sense suspension related information such as compression of the suspension, and to communicate the suspension related information to the CPD unit.
The CPD unit is configured to receive the suspension related information from the sensor structure and to convert the suspension related information into suspension-analysis information. The CPD unit stores the suspension-analysis information in an information storage device such as RAM. Additionally, the CPD unit is configured to display operator-selectable components of the suspension-analysis information to the vehicle operator for use in adjusting such vehicle suspension. Preferably, the operator-selectable components include percentage compression, inches of travel, rate of compression, rate of rebound, and full compression occurrences.
Optionally, the invented suspension monitoring system includes a remote digital computer configured to receive suspension-analysis information which is downloaded from the CPD unit. The digital computer is configured to permit further manipulation of the suspension-analysis information including displaying the suspension-analysis information as waveform data.